Moderate waves, taking a more pronounced long form; many white horses are formed.

Smaller trees sway.

6

40-50

25-31

22-27

2.4-4.0

Strong Breeze

Large waves begin to form; the white foam crests are more extensive everywhere.

Large branches in motion. Whistling heard in overhead wires. Umbrellas use becomes difficult.

7

51-62

32-38

28-33

4-6

Near Gale

Sea heaps up and white foam from breaking waves begins to be blown in streaks along the direction of the wind.

Whole trees in motion. Effort needed to walk against the wind.

8

63-75

39-46

34-40

4-6

Gale

Moderately high waves of greater length; edges of crests begin to break into spindrift. The foam is blown in well-marked streaks along the direction of the wind.

Twigs broken from trees. Cars veer on road.

9

76-87

47-54

41-47

~6

Severe Gale

High waves. Dense streaks of foam along the direction of the wind. Crests of waves begin to topple, tumble and roll over. Spray may affect visibility

Light structure damage.

10

88-102

55-63

48-55

6-9

Storm

Very high waves with long overhanging crests. The resulting foam, in great patches, is blown in dense white streaks along the direction of the wind. On the whole the surface of the sea takes on a white appearance. The tumbling of the sea becomes heavy and shock-like. Visibility affected.

Trees uprooted. Considerable structural damage.

11

103-119

64-73

56-63

9-14

Violent Storm

Exceptionally high waves (small and medium-size ships might be for a time lost to view behind the waves). The sea is completely covered with long white patches of foam lying along the direction of the wind. Everywhere the edges of the wave crests are blown into froth. Visibility affected.

Widespread structural damage.

12

120

74-95

64-80

>14

Hurricane

The air is filled with foam and spray. Sea completely white with driving spray; visibility very seriously affected.